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Patented Mar. 28, |899.

No. 622,|2a.

W. C. DAY.

COMBINED DRAFTING AND MEASURING TOOL.

(Application iled Oct. 1, 1898.)

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VILLIAM O. DAY, OF RUMFORD FALLS, MAINE, ASSIGNOR OF ONE-HALF TO WILLARD I. WHITE, OF SAME PLACE.

COMBINED DRAF'Il'ING ANDV IVIEASURING TOOL.

SPECIFICATION forming part of Letters Patent No. 622,128, dated March 28, 1899.

Application iiled October 1, 1898.

To @ZZ whom t may concern."

Be it known that I, WILLIAM O. DAY, of Rumford Falls, in the county of Oxford and State of Maine, have invented a certain new and useful Improvementin a Combined Drafting and Measuring Tool, of which the follow-I ing is a specification.

This invention relates to dividers for compasses, calipers, and similar drafting or measuring tools, and has for its object to facilitate the adjustment or spread of the legs in tools of this character.

To this end the invention consists in certain features of improvement in structure and arrangement which I shall now proceed to describe and claim.

Of the accompanying drawings, forming a part of this specification, Figure l represents a side elevation of a tool constructed in accordance with my invention and arranged to be used as dividers. Fig. 2 represents asimilar view of the tool arranged for use as outside calipers. Fig. 3 represents a similar view showing thevsame arranged for use as inside calipers. Fig. 4 represents an edge view of the upper part of the tool onl an enlarged scale. Fig. 5 represents a view ofthe same-with parts in side elevation and other parts in section. Fig. 6 represent-s a vertical sectional view. Fig. 7 represents a section on line 7 7 of Fig. 5 on an enlarged scale. Fig. S represents a section on line 8 8 of Fig. 5.

The same reference characters indicate the 'same parts in all the figures.

In the drawings, a a are the legs of the instrument, each of which is bent downwardly at a small angle near its'middle point, as shown. The lower portion of each leg I have represented 'as grooved and formed with a collar o3, having a set-screw o4, whereby end pieces or points of dierent form may besecured to the legs and readily removed, the form of the end piece depending upon the use to which it is desired to put the instrument. Thus in Fig. l the end pieces are rods t z', having sharpened points, which adapt the instrument for use as dividers. The substitution of a lead-pencil for one of these rods makes 'circle-Compasses of the instrument. Fig. 2 shows the instrument as provided with out- Serial No. 692,370. (No model.)

side caliper-legs jj, and Fig. 3 shows it provided with inside caliper-legsk k.

The legs o a are formed at their upper ends with ears c o2, which embrace a central pivotblock b, to which they are attached by two pivot-screws c c, headed and shouldered, as represented, and screwing into the block b from opposite sides.

On the under sides of the arms d a, above the bends in the latter, are formed recesses d5 a5, in which are pivoted on pins e e the upper ends' of two links e e of equal length. The lower ends of said links are pivoted on pins e2 e2 between ears formed on a collar f. Said collar slides on the lower end of a rod d, depending centrally between the legs a ct from the pivot-block b, and is provided with a set-screw f', having a milled head whereby the collar may be clamped or attached to said rod d at anypoint on the latter. The spreading apart of the legs a a', acting on the collar f through the links e e, moves said collar upward on the rod d in the direction of the pivotblock b, while the closing of the legs toward cach other produces a reverse movement of the collar along the rod. By screwing the setscrew f tight against the rod d, and thereby clamping the collar f to said rod, the legs a ce are held immovable at the distance apart to which they have been moved except when further adjusted by the slow-motion screw, which I shall now describe. `l

b is a sleeve formed on the lower side ot the pivot-block b and surroundingasocket b2, in which the upper end of the rod cl operates. Said rod is held from turning in the socket by means of a screw-stud' m, Fig. 6, passing through the wall of the sleeve h and entering a longitudinal groove cl' in the side of said rod d. In the upper end of said rod there is bored a socket d, which is screw-threaded to engage the lower end of a screw g. The screw g passes centrally through the pivot-block b, between the ends of the pivot-screws c c, as represented in Fig. 6, and is provided at its upper end with a milled head g', by means of which it may be turned. Said screw is further provided below its head with a boss or shoulder occupying a recess in the top of the pivot-block and formed with a circumferen- IOO tial groove g2. A pin h, passing transversely through the pivot-block b and engaging the groove g2, as represented in Figs. and 7, serves to prevent the screw from movinglongitudinally with respect to said pivot-block. Therefore when the screw g is turned in one direction or the other the rod d is raised or lowered in thc socket b2. When the collar f is clamped by means of its set-screw to the rod d, such turning of the screw g varies the spread ot' the legs a dV through a small distance.

In the operation of the instrumentthe legs a a may be brought to their approximate adjustment quickly by loosening the set-screw f and moving said legs apart or together, as

required, and then having tightened said setscrew the screw g may be work ed to bring the legs a a to an exact or minute adjustment. The particular shape or otlice of the instrument-legs is immaterial to my invention.

Having thus explained the nature of my invention and described a way of constructing and using the same, although without having attempted to set. forth all the forms in which it may be embodied or all the modes of its use, I declare that what I claim is l. An instrument of the character specilied, comprising a pair of legs pivoted together, a longitudinally-movable rod extending from the pivot between the legs, a pair of links pivoted to the legs, a sleeve pivoted to the links and surrounding the rod, and holding it in central position between the legs, said sleeve being normally loose on the rod so that the legs may be quickly adjusted in unison, a fastening device on the sleeve whereby it may be made fast to the rod to move therewith, and a screw journaled to rotate in the said pivot and engaged as described with the rod, said screw cooperating with the sleeve, its fastening device, and the rod and links, to give the legs a minute adjustment in unison, and the said sleeve serving to equalize the adjustment of the legs each side of the rod during either quick or minute adjustment.

2. An instrument of the character-described,

`comprising the pivot-block b, the legs a a,

pivoted together, the rod d internally screwthreaded at its upper end, the sleeve f Iitted to slide on the rod, the links e e pivoted to said legs and sleeve, means for clamping the sleeve to said rod, the screw g engaged with the internally-screw-threaded portion of the rod, and a retaining connection between said screw and the pivot-block.

3. Aninstrument of the charaoterspeciiied, comprising the pivot-block b, the legs a a having ears which embrace said block, the pivotscrews c c connecting said ears with the block, the rod (l, a connection between said rod and the legs, and the screw g passing centrally through the block b, between the ends of the screws c c, and engaging the rod d.

In testimony whereof I have aiiixed my signature in presence of two witnesses.

I IVILLIAM C. DAY. VVi'rnesses:

M. R. BILLINGs, Il. C. WHITTEMORE. 

